Remember, the main limit right now on the gas supply is refining capicity, not oil cost. The oil companies would love to be able to build more refineries, but the enviros throw a hissy fit every time they try to do so. In the example you gave, I would imagine the Southeast has a lot more refining capacity (especially in Texas & Louisiana) than the Northwest, explaining the price difference. Also note, since oil is a commodity, it doesn't matter if it comes from Alaska, or OPEC, or the Moon. The price is going to be the same everywhere, excluding a bit for transportation cost.